Some clap v3.x Subcommand derives cause clippy errors since Rust 1.69.0

[hds]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Rust Version

rustc 1.69.0 (84c898d65 2023-04-16)

Clap Version

clap 3.2.23, clap_derive 3.2.18

Minimal reproducible code

#[derive(clap::Subcommand)]
enum Command {
    One,
}

fn main() {}

Steps to reproduce the bug with the above code

Run clippy with defaults:

cargo clippy

Actual Behaviour

This results in the following error in clippy.

error: this looks like you are trying to swap `__clap_subcommand` and `clap::Subcommand`
 --> src/main.rs:1:10
  |
1 | #[derive(clap::Subcommand)]
  |          ^^^^^^^^^^^^^^^^
  |
  = note: or maybe you should use `std::mem::replace`?
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#almost_swapped
note: the lint level is defined here
 --> src/main.rs:1:10
  |
1 | #[derive(clap::Subcommand)]
  |          ^^^^^^^^^^^^^^^^
  = note: `#[deny(clippy::almost_swapped)]` implied by `#[deny(clippy::correctness)]`
  = note: this error originates in the derive macro `clap::Subcommand` (in Nightly builds, run with -Z macro-backtrace for more info)

error: could not compile `clap-deny-correctness` due to previous error

Expected Behaviour

The clippy error is problematic because the attribute that specifies deny is inside the macro itself. That means that as a user of Clap, I'm not able to override the deny.

Specifically this attribute:

#[deny(clippy::correctness)]

Which is present in 7 specific places in clap_derive.

Additional Context

For Clap v4.x, these attributes were already removed in #4739.

Doing the same in the v3-master branch is probably sufficient

Debug Output

No response

[epage]

I am fine with someone fixing this in v3-master.

[guswynn]

@epage Can we #[allow(almost_swapped)] in v3 instead of just removing the deny clause? It's quite onerous to allow these warnings, as annotating the struct/enum with #[allow(clippy::almost_swapped)] doesn't work, you have to use a #![allow(clippy::almost_swapped)] at the module level. If one wants to limit the scope of this allow, they have to introduce a new submodule for all their clap-derived types.

I'm willing to make the pr to do this!

[epage]

I will say that the idea is to match clap v4. We should treat anything in v3 as backports. I should have looked more closely to confirm that. I would be open to a PR if it makes things more aligned with v4. If someone wants something that is not in v4, we should put it in v4 first.

[hds]

Adding #![allow(clippy::almost_swapped)] was already done in v4 (in #4735). I didn't include it in #4858 for the sake of keeping it as small as possible. If @epage is happy for this to also be backported, then I can create the PR.

[epage]

I would be fine with that

[guswynn]

Thanks for following up here @hds !

[hds]

I've backported the v4 change #4735 to v3-master, now available in #4866.

The same docs test is failing that failed in the previous PR on that branch.

[epage]

I believe this is now resolved, so I'm going to close this. If there is something specific to this issue that still isn't resolved, let us know!